Automatic screwdown-control system for rod mill



R. R. SNOW 2,933,956

AUTOMATIC SCREWDOWN-CONTROL SYSTEM FOR ROD MIL April 26, 1960 3Sheets-$heet 1 Filed Jan. 30, 1958 INVENTOR.

49/66 4490 4?. SNOW April 26, 1960 R. R. SNOW 2,933,956

AUTOMATIC SCREWDOWN-CONTROL SYSTEM FOR ROD MILL Filed Jan. :50, 1958 3Sheets-Sheet 2 Q-R l mm INVENTOR. 4/5/4440 e .s/von April 1960 R. R.SNOW 2,933,956

AUTOMATIC SCREWDOWN-CONTROL SYSTEM FOR ROD MILL Filed Jan. so, 1958 3Sheets-Sheet 5 Izov 34 F I l I V l I I 1 T l INVENTOR. L 19/0/44 0 4.s/von United States Patent AUTOMATIC SCREWDOWN-CONTROL SYSTEM FOR RODMILL Application January 30, 1958, Serial No. 712,222 3 Claims. (Cl.80-56) This invention relates to mills for hot rolling a p1urality ofbillets simultaneously, such as those used in converting billets to wirerod. In particular, it concerns a system for adjusting the millscrewdowns in accordance with the particular passes of the mill in whichbillets are actually present.

In hot-rolling billets into wire rod, a roll setting appropriate for theconditionin which all the mill passes are occupied by billets will notbe proper if some of the passes are empty. That is to say, if the millscrews are properly set for rolling four billets simultaneously, forexample, and one billet is dropped because of a cobble or any otherreason, the resulting reduction of the roll spring will cause theremaining billets to be overreduced. This necessitates a slight backingoff of the screws to cause the mill to effect only the proper reductionand no more. Such compensating adjustment is customarily made manuallybut is too slow for rapid changes and is therefore made only when achange continues for a substantial period. It is the object of myinvention to provide automatic means responsive to the presence ofbillets in the mill passes, for effecting this adjustment.

In a present preferred embodiment of the invention, I employradiation-responsive means directed at the paths of heated billetstraversing the several passes of a mill stand. I also provide manuallysettable means effective when operative, to bring the mill screws topredetermined positions through operation of a conventional screwdownmotor and controller. Selector relays controlled by theradiation-responsive means in accord with the billetstraversing themill, serve to connect the proper manually settable means in circuit tooperate the screwdownmotor controller to effect the necessaryadjustment.

A complete understanding of the invention may be obtained from thefollowing detailed description and explanation which refer to theaccompanying drawings illustrating the present preferred embodiment. Inthe drawings:

Figure l is a diagrammatic side elevation of a mill showing theradiation-responsive means in position thereon;

Figure 2 is an end elevation corresponding to Figure 1;

Figure 3 is a diagrammatic showing of the relationship between theradiation-responsive means, the manually settable means and the selectorrelays as a group;

Figure 4 is a circuit diagram of the radiation-responsive means and theselector relays; and

Figure 5 is a circuit diagram of the controller for one screwdown, alongwith the manually settable means.

Referring now in detail to the drawings and, for the present,particularly to Figures 1 and 2, a stand of a continuous rod-mill,preferably the first stand thereof, includes rolls 11 journaled inspaced housings 12 provided with screws 13 for adjusting the rollsetting. Motors 14 mounted on brackets 15 drive the screws individually.Rolls 11 have several matching pairs of grooves 16 therein, eachcooperating pair defining a pass 2,933,956 Patented Apr. 26, 1960 forreducing a billet. The billets in the several passes illustrated aredesignated 17, 18, 19 and 20. Entry and exit guides 21 and 22 direct thebillets into and out of the'several passes.

A post 23 adjacent stand 10 but spaced to one side thereof has a lateralarm 24 at its upper end to which is pivoted a tiltable arm 25. Arm 25 isnormally disposed in the horizontal position shown in solid lines inFigure l, overhanging the pass line between the rolls 11. It may,however, be uptilted to the chain-line position so as to be out of thewa Sensing devices 26, 27, 28, 29 responsive to infra-red radiation arespaced along arm 25 in locations such that, when the arm is in theillustrated position, the devices will receive radiation from heatedbillets traversing the passes of the mill stand 10. Devices such as 26are well known per se and are available commercially. They are providedwith contacts 30, 31, 32 and 33, respectively (see Figure 4) which arenormally open but are closed when infra-red radiation of predeterminedintensity impinges thereon.

Figure 3 shows the control system of my invention schematically. Foreach screwdown of the stand 10, I provide a plurality of manuallysettable devices, e.g., otentiometers, 34, one potentiometer of each setcorresponding to a predetermined condition in respect to the presence ofbillets in the several mill passes or their absence therefrom, asillustrated in the chart at the right of Figure 3. More specifically,the uppermost potentiometers 34 are manually preset to bring about theproper setting of the two mill screws (through means to be describedhereafter) for rolling billets in all four passes simultaneously to thedesired size, as indicated in the chart by blocks 35. Similarly, thenext potentiometers in the row are set for the roll setting appropriatefor rolling three billets when the second one from the left has beendropped, as shown at 36. The remaining potentiometers are set for theother conditions as indicated respectively, by blocks 37, 38, 39 and 40,viz., third billet dropped, first billet dropped, fourth billet droppedand no billets in the mill.

As will be further explained by reference to Figure 4, the existence ofone or the other of the conditions illustrated schematically in Figure 3at 35, 36, 37, 38, 39 and 40, will bring the corresponding otentiometersin to play to effect a setting of each of the mill screws appropriate tothe condition observed by devices 26 through 29. This is accomplished bya selector S, the circuit of which is shown in Figure 4, and acontroller shown in Figure 5, actuated by the selector. Referring now toFigure 4, the contacts 30, 31, 32 and 33 of devices 26, 27, 28 and 29,when closed, energize relays 41, 42, 43 and 44, respectively. Each ofthese relays actuates a plurality of contacts 41a, 41b, 41c, 41d and41e, for example, some normally open and some normally closed as shown.

The several contacts of the relays 41, 42, 43 and 44 constituteinterlocks controlling condition-selector relays 45, 46, 47, 48 and 49.The arrangement of the contacts is such that when all of relays 41, 42,43 and 44 are energized, relay 45 will be energized but the circuits forrelays 46, 47, 48 and 49 will be open. Similarly, when relay 42 isdeenergized, relays 41, 43 and 44 remaining energized, the circuit forrelay 46 will be closed but the circuits of relays 45, 47, 48 and 49will be open. The remaining circuits for relays 47, 48 and 49 aresimilar. The overall result is that one and only one of relays 45, 46,47, 48 and 49 will be energized for each of the conditions illustratedat 35, 36, 37, 38 and 39 of Figure 3.

Each of relays 45, 46, 47, 48 and 49 has a normally closed contact(e.g., 45a) and a normally open contact (e.g., 45b). The normally closedcontacts of all the tive to produce the. desired adjustment.

. apparent that the connection triode 52 will cause a' screw adjustmentgoverned by the relays are connected in series with a relay 50." Thus,

called into play is amplified and applied to the grid of a secondamplifier triode. 53. The resulting output of the latter energizes adifierential relay,54. This relay has. two normally opencontacts 54a andS4band func tions to close 54a on an increase in current through triod'e53 and contact 54b on a decrease in such current.

' Contacts 54a and 54b control a reversing contactor panel for one ofthe screwdown motors'14, causing upward or downward movement of thescrew as called for by the setting'of thepotentiometer which isconnected to triode 52. Balancing potentiometers 55 and 56 are operatedin accordance withthefscrew movement efiecjustment is completed, theseotentiometers red'uceflthe voltages on the grids oftriodes 52 and 53 tovalues such that no current fiows through relay 54. It will thus be.

existing setting of that potentiometer.

The controller 51 is for one screwdown motor. A similar controller isprovided for the other motor. Duplicate contacts on relays '45, 46,vetc. like contacts 45b, 46b, etc. control the connection ofpotentiometers'34 for the other screw to the second control system.

The'invention greatly reduces the rod-size variations previouslyoccurring and minimizes the number of cobbles resulting from buckling byautomatically compensating the setting of, the rolls of the first standof a rod The voltage.

of any potentiometer 34 to' mill in accord with the number ofbilletsactually'in the mill. As a result, the invention produces anincreased 7 yield anda better quality of product.

Although I have disclosed hereinthe preferred embodiment of myinvention,;I;intend to cover as well any change or modification thereinwhich may be made withoutdeparting from the'spirit and scope of theinvention.

I claim: 7 .1. In a rollingmillxincludinga pairlof cooperating rollshaving a pluralityof sets of matching. grooves. de-

' fining several passes for reducing a plurality of billetssimultaneously, roll-adjusting screws, a motor driying one of the screwsand a controller for said motor, the combination therewith of aplurality of manually settable means adapted, respectively, to causethecontroller to adjust the rolls to difierent settings, depending on whichsets of grooves are occupied. bybillets undergoing reduction at a giventime, and means responsive tto'the presence of billets: in said sets ofgrooves, respectivel a. effective to connect a selected one 02 saidmanually settable means to said controller." I a 2. The combinationdefined ii -claim- 1, characterizedby said :responsive means including;,a.plurality' of relays 7 affected by radiation from hot bodies, eachof said re.-

lays being positioned to -receive:.radiation from a billet in one ofsaid passes. i

3. The combination defined in claim 2,. characterized pivoted'ther'eto'adapted to extend as a cantilever beam by a post standing. adjacent:said mill having an over the mill, said radiation relays being spacedalongsaid arm.

References Cited in the filefof this patent, UNITED, STATES PATENTSShayne et al. Jan. 18, 1944 1,813,539 Hurley July 7; 1931- '1,951,426Littler Mar. 20,v 1934 2,289,410 Dahlstrom July 14,,l942. 2,339,359

